Means for regulating double-current dynamo-electric machines.



No. 679,8!31 Patented Aug. 6, mm.

J. L. WODDBBIDGE.

MEANS FOR REGULATING DOUBLE GURRENT'DYNAMO ELECTRIC MACHINES.

(Application filed Apr. 30, 1901.)

(No Model.)

PATEN Enron.

JOSEPH LESTER l/VOODBRIDGE, OF PHILADELPHIA, PENNSYLVANIA.

MEANS FOR REGULATiNG DOUBLE-CURRENT DYNAMO-ELECTRIC MACHINES.

SPECIFICATION forming part of Letters .Patent No. 679,813, dated August6, 1901. Application filed April 30, 1901 Serial N0.;58,il95. (Nomodel.)

To ctZZ whom it may concern.-

Be it known that I, J-osEPH LESTER W001)- BRIDGE, a citizen of theUnited States, residingin the city of Philadelphia, in the county ofPhiladelphia, State of Pennsylvania, have invented certain new anduseful Improvements in the Means for Regulating Double-Current Dynamo-Electric Machines, of which the following is a specification.

My invention relates to those dynamo-electric machines which aredesigned to develop orutilize both direct and alternating currents inone and the same armature-winding, and

under the title double-current dynamo-electric machines, which I haveused throughout this specification and claims, I intend to include anydynamo-electric machine provided with both a commutator andcollectorrings connected to the same armature-winding, whether themachine, first, is driven by some external source of power and deliversboth alternating and direct currents, or, sec ond, receives directcurrents and delivers al ternating currents, or, third, receivesalternating currents and delivers direct currents. The first case isthat of the double-current generator, and the second and third'cases arerotary converters. My invention is equally applicable to all three, andin using the phrase doublecurrent dynamo-electric machine I intend toinclude them all; Also in referring to the electromotive force, whetheralternating or direct, generatedin the armature of such a machine Iintend to include not only such electromotive forces as are 00-directional with the current, involving the function of generator, butalso such as are counter to the current or to some'applied electromotiveforce, involving the function of motor.

It is the object of my invention to provide an improved means forcontrolling and varying the relation between the alternating and thedirect current electromotive force developed in the armature of adouble-current dynamo-electric machine. Up to the present time verylittle, if any, modification has been possible in the relation betweenthese two electromotive forces. In the double-current generator theymust rise or fall together with any variation of speed or fieldexcitation.

In a rotary converter-receiving direct currents at constant voltage ifany attempt is made to increase the alternating electromotive force bystrengthening the fields the only effect will be to reduce the speed ofrotation,

the alternating voltage remaining the same. If the rotary is receivingalternating currents at constant electromotive force and deliveringdirect currents, the usual method of controlling the direct-currentvoltage, particularly where it is to be done automatically, consists inaltering the field excitation; but such an alteration will still changeboth the direct-current voltage and the alternating counterelectromotive force together, and for conditions of equilibrium willnecessarily be accompanied by a change of phase relation between theapplied and the counter alternating electromotive force unless theformer is also changed. Ordinarily this change in phase relation isbrought about more or less gradually by a temporary change in armaturespeed, the armature running ahead of or falling behind its former phaseposition, according as the excitation is diminished or increased, untilit reaches its new position of equilibrium. Because of the inertia ofthe armature this method of regulation is sluggish in its action andintroduces excessive fluctuations of current in the alternatingsupply-lines and produces a tendency in the armature to seesaw and bethrown wholly out of step. The equilibrium is not reestablished untilthe phase position of the armature is altered sufficiently to introduceinto the alternating supplylines Wattless currents of such magnitude inmany cases as to cause exceedingly objectionable effects on the heating,efficiency, and regulation of the alternating-current apparatus andtransmission-lines, as well as on the steadiness of armature speeds.

Now it is the object of my invention to provide improved means forregulating the ratio between the alternating and the direct currentvoltage developed by a double-current dynamo-electric machine whichshall permit a comparatively wide variation of that ratio withoutintroducing objectionable wattless currents into the alternatingcircuits or causing the other objectionable results above mentioned.While it is known that on account of the difficulties above cited noapprcciable variation in the relation between the alternating and thedirect current voltage developed by a double-current dynamoelectricmachine as heretofore constructed can be effected practically and thatin the case of a rotary receiving alternating currents and deliveringdirect currents when a considerable variation in the direct-currentvoltage is desired, it has been found necessary to alter the alternatingvoltage simultaneously either by some method of hand regulation orautomatically by means of the inductive effects of the wattless currentsabove referred to in the alternating circuits, yet it is also known thatin two difierentlyconstructed double-current machines the ratio of thealternating to the direct current voltage may be markedly different onaccount of the difference in the relative breadth of the pole-faces andthe resulting difference in the distribution of the lines of magneticforce and in the shape of the wave of alternating electromotive force.For example, two rotaries each of the same number of phases andsubjected to the same alternating electromotive force may be constructedto give quite different direct current electromotive forces without ineither case introducing objectionable wattless currents into thealternating circuits by proportioning the pole-pieces differently ineach case.

Now it is the object of my invention to provide means for varying andcontrolling the relation between the alternating and the direct currentelectromotive forces of a doublecurrent dynamo-electric machine over acomparatively wide range by altering the relative distribution of thelines of magnetic force over the pole-face, and thus changing the shapeof the wave of alternating electromotive force. Thus by concentratingthe lines of force near the middle of the pole-face they will becomemore effective in producing alternating voltage and the ratio ofalternating to direct current electromotive force may be thus increased,the latter electromotive force being dependent not upon the distributionof the lines of force, but upon the total number of such lines.Conversely, if thelines of force are spread over a broad pole-face orconcentrated near its tips they become less effective in producingalternating electromotive force (the lines of opposite polarity from twoadjacent pole-faces counteracting each other when included within thesame phase section of the armature-winding) and the ratio of alternatingto direct current electroinotive force will be reduced.

In the accompanying drawings, Figure 1 illustrates the general scope ofmy invention, and Figs. 2 and 3 show modifications thereof.

In Fig. 1, AA represent the armature-winding of a three-phasedouble-current dynamoelectric machine, the armature being supposed torotate in the direction shown by the arrow.

B and 3' are respectively the positive and negative direct-currentbrushes, shown for simplicity as bearing directly upon thearmature-winding, but which will of course be understood to bear upon acommutator connected therewith in actual practice. These brushes areshown connected by circuits 14c and to the terminals 1 and 16,respectively.

ct, b, and c are collector-rings which are connected to thearmature-winding at three equidistant points and upon which bear thebrushes 0., b, and c, which constitute the alternating-current terminalsof the machine.

N and S are the north and south poles, respectively, and are eachdivided into three separate horns or pathsfor the magnetic flux n n nand s, s, and The divisions between these magnetic paths may extendentirely through to the pole-face, as shown in Fig. 1, or may be bridgedover at the pole-face, as shown in Fig. 2, or these divisions may extendto the yoke or frame of the machine, as in Fig. 3, giving these magneticpaths the appearance of separate poles. It will be observed, however,that in the construction shown in Fig. 3 n, n, and n will be of likepolarity and constitute one pole, the same as in Figs. 1 and 2. On theleading horns n and s in Fig. 1 are shown series windings 1 7 8 9 10 1112 13 2. On the middle horns n and s are shown series windings 3 17 1810 20 21 22 23 t. On the trailing horns n and s are shown serieswindings 5 24: 25 26 27 28 29 30 6. By means of the connections shownbetween terminals 2 and 3 and between l and 5 these three sets ofwindings are connected in series with each other and with the positiveside of the direct-current circuit, terminal 6 constituting the positiveterminal of the machine in relation to the external direct-currentcircuit. The effects of these three sets of windings on the respectivepole horns which they embrace may be modified and adjusted by means ofthe three adjustable shunts d, e, andf. Assuming that the machine isdelivering direct currents at its direct-current terminals, thedirection of these currents will be as shown by the arrows, and it willbe noted that the effect of these currents in the series windings on theleading and trailing horns of the poles will be to increase the magneticflux in them, while the current in the series windings on the middlehorns will decrease the magnetism therein. It will be seen, therefore,that any increase in the direct-current output of the machine willstrengthen the edges of the magnetic field and weaken it in the middle.The effect of this will be to increase the ratio of the direct-currentelectromotive force to the al ternating electromotive force, and if theamount of current in the several windings be properly adjusted by meansof the adjustable shunts d, e, andfany one of several effects may beproduced. If the edges of the field are considerably strengthened andthe middle weakened to a less extent, the total magnetic flux, andtherefore the direct-cur- 'rent voltage, will be increased, while thealternating voltage will remain stationary. This arrangement would be ofadvantage where the machine is driven by an outside source of power andis delivering both direct and alternating currents,as it permits thecompounding or overcomponnding at the direct-current terminals withoutinterfering with the regulation of the alternating terminals. If theedges of the fields are still further strengthened and the middle stillfurther weakened, the same rise of direct-current electromotive forcemay be produced, accompanied by a fall of the alternating electromotiveforce. This is of special advantage where the machine is operating as arotary converter and is driven by the alternating currents received atits collector-rings. The fall in alternating electromotive force in thearmature may thus be made to correspond with any drop in the alternatinglines due to the increased current in them. Still another effect may besecured in the latter case. The increased currentin the alternatinglines may cause a change in the phase of the applied alternatingvoltage, making it desirable to shift the phase of the counterelectromotive force correspondingly. This may readily be done byadjusting one of the shunts d or f so as to strengthen the leadingpole-horns to a greater extent than the trailing horns, or Vice versa,according to the direction in which it is desired to shift the phase ofthe alternating counter electromotive force. Similarly by strengtheningthe excitation of one side of the fields more than the other thedistorting ef fects of armature reaction on the fields may becounteracted.

In addition to the above-described series windings I have shown on thediagram two shunt-windings. One of these, I 56 57 58 59 6O 61, is theprincipal shunt-winding, embracing the north and south poles (N and S)in their entirety, as in the ordinary type of gen erator or motor, thecurrent therein being regulated by means of the rheostat R included inthe circuit. The other or auxiliary shuntwinding 1 32 33 34 35 36 37 3839 4O 41 42 43 44 45 46 is wound on the several pole-horns n n n s s sseparately and the current therein is controlled by the rheostat R. Itwill be noted that those parts of this latter winding 34 35 and 42 43which embrace the middle horns n and s are wound in the oppositedirection from those parts which embrace the outer horns n n 8 3 Currentin this wind ing flowing in the direction shown by the arrows willtherefore increase the magnetism in the outer horns and decrease that inthe middle horns. If the amount of this increase produced in each of theouter horns is equal to the amount of decrease in each of the middlehorns, then the effect will be to increase the direct-currentelectromotive force without altering the alternating electromotiveforce, and this effect may be regulated by the rheostat R. The two arms39 and p of the rheostats R and R are carried on the same spindle m,operated by the hand-wheel z, and may be attached to or released fromthis spindle by tightening or loosening the thumbscrews 00 and 00 andthus either rheostat may be operated independently of theother or bothmay be operated simultaneously. These two rheostats are so connectedthat motion of the arm 19 in the direction shown by the arrow willincrease the current in the principal shunt-winding, thus increasingboth the direct-current and alternating-current electromotive force,while motion of the arm 19 in the same direction will decrease thecurrent in the auxiliary winding, thus decreasing the direct-currentelectromotive force without al- I tering the alternating electromotiveforce. If the rheostats are so designed that the increase in thedirect-current electromotive force due to a movement of the arm 19 isequal to the decrease in this electromotive force due to the sameangular movement of 10, these two effects will neutralize each other andthe simultaneous motion of the two arms 10 and 20 will have no eifect onthe directcurrent electromotive force, but will alter the alternatingcurrent electromotive force. Thus by changing the position of p we canvary the direct-current electromotive force without altering thealternating-current electromotive force. By moving p and p together wecan vary the alternating-current electromotive force without alteringthe direct-current electromotive force, and by moving 19 only we canalter both electromotive forces simultaneously, the total amount of:magnetic flux being varied without altering its distribution over thepole-face.

In speaking of the pole-face it will be understood that I refer to thewhole area between the pole-tips g h or 71 7c and not simply to one ofthe portions into which this surface may be divided by the divisionsreferred to. It will also be understood that my invention applies todouble-current machines IIO having any number of poles and designed toutilize or develop alternating currents of any number of phases. Nor doI confine myself to any particular means for altering the distributionof the magnetic flux over the poleface nor to any particular means fordoing this automatically. I have described an arrangement for varyingthis distribution automatically with variations of the direct-currentoutput or intake; but a similar automatic regulation of thisdistribution could be made to accompany changes in thealternating-current intake or output by causing the currentsin theseries or auxiliary shunt-windings to vary with said intake or output byany of the means well known to those familiar with the present state ofthe art.

It will be obvious to those skilled in the art to which the inventionrelates that modifications may be made in details without departing fromthe spirit thereof. Hence I do not limit myself to the preciseconstruction and arrangement of parts hereinabove set forth, andillustrated in the drawings; but,

Having thus described the nature and ob jects of the invention, what Iclaim as new, and desire to secure by Letters Patent, is

1. In combination, in a double-current dynamo-electric machine, anarmature having a single winding connected both to the commutator and tocollector-rings and a field-magnet having its poles each divided intothree paths for the magnetic flux by divisions in a general direction atright angles to the adjacent direction of armature peripheral motion,and means for varying disproportionately or oppositely the quantity ofmagnetic flux in each of the three paths, substantially as described.

2. In combination, in a double-current dynamo-electric machine, anarmature having a single winding connected both to the commutator and tocollector-rings and a field-magnet having its poles each divided intothree paths for the magnetic flux by division in a general direction atright angles to the adj acent direction of armature peripheral motionand windings embracing separately these several paths, said windingsbeing so designed and connected that variations in the electric currentsflowing through them shall vary disproportionately or oppositely thequantity of magnetic flux in each of the three paths, sub stantially asdescribed.

3. In combination, in a double-current dynamo-electric machine, anarmature having a single winding connected both to the commutator and tocollector-rings, and a field-magnet having its poles each divided intothree paths for the magnetic flux by divisions in a general direction atright angles to the ad jacent direction of armature peripheral motionand windings embracing separately these several paths, and means for sovarying the currents in each of said windings as to causedisproportionate or opposite effects on the quantity of magnetic flux ineach of the several paths, substantially as described.

4. In combination, in a double-current dynamo-electric machine, anarmature having a single winding connected both to the commutator and tocollector-rings, and a field-magnet having its poles each divided intothree paths for the magnetic flux by division in a general direction atright angles to the adjacent direction of armature peripheral motion,and windings embracing separately these several paths, said windingsbeing connected in series between one of the direct-current brushes ofthe machine and the main machine terminal of like polarity, saidwindings being so relatively proportioned and connected that variationsin the currents flowing in them shall vary disproportionately oroppositely the quantity of magnetic flux in each of the three paths,substantially as described.

5. In combination, in a double-current dynamo-electric machine, anarmature having a single winding connected both to the commutator and tocollector-rings, and a field-magnet having its poles each divided intothree paths for the magnetic flux by divisions in a general direction atright angles to the adjacent direction of armature peripheral motion, awinding embracing in series the first or leading horns of the severalpoles, another winding embracing in series the middle horns of theseveral poles and a third winding embracing in series the last ortrailing horns of the several poles, these three windings beingconnected in series, between one of the direct-current brushes of themachine and the main machine terminal of like polarity and so connectedthat a flow of current will have a like effect on the quantity ofmagnetic flux in all the middle horns and the opposite effect on thequantity of magnetic flux in all of the outer (leading and trailing)horns, substantially as described.

6. In combination, in a double-current dynamo-electric machine, anarmature having a single winding connected both to the comm utator andto collector-rings, and a field-magnet having its poles each dividedinto three paths for the magnetic flux by divisions in a generaldirection at right angles to the adjacent direction of armatureperipheral motion, a Windin g embracing in series the first or leadinghorns of the several poles, another winding embracing in series themiddle horns of the several poles and a third winding embracing inseries the last or trailing horns of the several poles, these threewindings being connected in series, between one of the direct currentbrushes of the machine and the main machine terminal of like polarityand so con nected that a flow of current will have a like effect on thequantity of magnetic flux in all the middle horns and the opposit effecton the quantity of magnetic flux in all the other (leading and trailing)horns, and adjustable shunts across the terminals of each of the saidwindings, as and for the purpose described.

7. In combination, in a double-current dynamo-electric machine, anarmature having a single winding connected both to the commutator and tocollector-rin gs,a field-magnet having its poles each divided into threepaths for the magnetic flux by division in a general direction at rightangles to the adjacent direction of armature peripheral motion, awinding consisting of separate coils embracing each of said paths, thecoils of the outer (leading and trailing) horns of the poles being woundin the same relative direction and the coils on the middle horns beingwound in the opposite direction, and means for varying at will theamount of current in said windings, substantially as described.

8. In combination, in a double-current dy namo-electric machine, anarmature having a single winding connected both to the commutator and tocollector-rings,a field-magnet having its poles each divided into threepaths for the magnetic flux by divisions in a general di- IOO reetion atright angles to the adjacent direction of armature peripheral motion ,aprincipal winding embracing each pole as a whole, an auxiliary windingconsisting of separate coils on each of the pole-h0rns,the coils 0n theouter (leading and trailing) horns being wound in the same relativedirection, and the coils on the middle horns being wound in the oppositedirection, and means for varying at will 10 either the current in theprincipal winding 0r the current in the auxiliary winding, or thecurrent in both windings simultaneously,substantially as described.

In testimony whereof I have hereunto signed my name.

J. LESTER \VOODBRIDGE.

In presence of JOHN R. WILLIAMS, WM. 0. DU BoIs.

